Fig. 5. Immunofluorescent analysis of localization of RAD51, DMC1 and RPA proteins (green) during male meiosis. Expression of these proteins was compared between control (Brca2 Ko/+; Tg/+, A,D, F) and rescued (Brca2 Ko/Ko; Tg/+, B,E,G) spermatocytes. Nuclei are also stained with SYCP3 antisera (in red). (A,B) RAD51 foci are visible on chromatin of control spermatocytes during the zygotene stage, but most of the rescued spermatocytes showed little or no RAD51 foci. (C) Semi-quantitative analysis of RAD51 foci per spermatocyte at the leptotene and zygotene stages reveals the reduction in number of foci in rescued spermatocytes. The majority of control spermatocytes had 100-250 foci per nuclei (>100 group). In the rescued spermatocytes, 58% had no foci while majority of nuclei in the 1-100 group had fewer than 10 foci, although a small number had 20-30 foci per nuclei. (D,E) Similar to RAD51, there is marked reduction in the number of DMC1 foci in rescued spermatocytes compared with control cells. (F,G) RPA protein is present in abundant foci in rescued spermatocytes compared with control spermatocytes.